This invention relates to synchronising devices.
Time synchronisation in computer and communication systems is important for performing time-sensitive tasks. A lack of synchronisation between devices can cause various issues. For example, in a wireless media system, a lack of synchronisation between different media playout devices (e.g. speakers) in the system may cause playback of the media to be out-of-sync. Other time-sensitive tasks where accurate synchronisation is critical include synchronising times for communicating (e.g. in time division multiple access communication systems), accurate time-stamping (e.g. for high-frequency trading), timing for global navigation satellite systems, etc.
A lack of synchronisation between devices may be caused by slight differences between clocks running at those devices. Even when clocks are initially set accurately, they will differ after some amount of time due to clock drift, which may be caused by, for example, the clocks counting time at slightly different rates, environmental factors such as temperature differences, relativistic effects, etc. Current methods of synchronising multiple devices involve using software to continuously monitor the time difference between the clocks of those devices and then updating a clock source (e.g. a phase lock loop). Such continuous monitoring requires a processor to be constantly powered on, which drains power. Furthermore, updating certain clock sources, such as phase locked loops, also requires some additional time for the clock to stabilise. There is, therefore, a need for improved ways of synchronising devices.